Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022716 (Menkes)
 1,057 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Menkes' disease (MD) and occipital horn syndrome (OHS) are allelic X-linked disorders caused by mutations in the copper ion transporting ATPase, ATP7A. Genetic, phenotypic and biochemical data suggest that mottled mutants in the mouse, which range in severity and phenotype, are caused by mutations in Atp7a, the mouse homologue of ATP7A. As the only causal mutation in Atp7a has been reported in one very mild allele thought to be a model for OHS, Atp7aMo-blo (mottled blotchy), we sequenced the entire 4.5 kb coding region of three other mottled mutants, two of which are thought to be models for classical MD (AtpaMo-br, AtpaMo-13H) and one with a slightly milder phenotype (Atp7aMo-vbr). Although no causal mutation was found in Atp7aMo-13H, mutations which can be predicted to affect Atp7a function were identified in Atp7aMo-br and Atp7aMo-vbr. A 6 bp deletion of nucleotides 2478-2483, which can be predicted to affect the correct processing of the protein, was found in Atp7aMo-br and an A3189-->C nucleotide change, which results in lysine-->threonine amino acid substitution in the phosphorylation domain, was found in Atp7aMo-vbr. Thus we provide further proof that mottled mutants will provide excellent models for MD as well as OHS.
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PMID:Mutation analysis provides additional proof that mottled is the mouse homologue of Menkes' disease. 914 45

We have investigated the cDNA sequence of the copper-transporting P-type ATPase (Atp7a) gene of the macular mouse, a model for human Menkes disease. A point mutation (T to C) that results in substitution of proline for serine in a putative eighth transmembrane domain of the ATP7A was identified. This contrasts with abnormalities identified in the Atp7a of other mottled mouse strains: lack of expression of Atp7a mRNA in the dappled mouse, and a splicing mutation in the blotchy mouse.
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PMID:A serine-to-proline mutation in the copper-transporting P-type ATPase gene of the macular mouse. 916 84

Wilson disease (WD), an autosomal recessive disorder of copper transport, is characterized by impaired biliary excretion and by impaired incorporation of copper into ceruloplasmin. Toxic accumulation of copper causes tissue damage, primarily in the liver, brain, and kidneys. The gene for WD (ATP7B) has been cloned, and the protein product is predicted to be a copper-transporting P-type ATPase with high amino acid identity with that for Menkes disease, an X-linked disorder of copper transport. Mutation screening in WD patients has led to the identification of at least 40 mutations. In addition, haplotype analysis using three dinucleotide-repeat markers, D13S314, D13S301, and D13S316, has been a useful indicator of specific mutations. We have determined haplotypes for the patients and their parents and sibs, in 21 unrelated WD families from Japan. Twenty-eight different haplotypes were observed on 42 WD chromosomes. In all the patients, the ATP7B coding sequence, including the intron-exon boundaries, was screened for mutations, by SSCP, followed by direct-sequence analysis of the shifted fragments. We identified 13 mutations, of which 11 mutations are novel, including 7 mutations-1 insertion, 4 deletions, and 2 missense mutations-in the coding region. The mutations reported in previous studies are 2299insC and Arg778Leu. Two patients were shown to have the 2299insC mutation, which has occurred in many different haplotypes in several populations, indicating a mutation hot spot. Primer-extension analysis of ATP7B mRNA has revealed multiple transcription start sites. Four of the novel mutations (three 1-bp changes and one 5-bp deletion) occur in the 5' UTR and may result in altered expression of the WD gene.
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PMID:Haplotype and mutation analysis in Japanese patients with Wilson disease. 919 63

The brindled mouse mutant (Mo(br)) is the closest animal model of the human genetic copper deficiency, Menkes disease, which is presumed to be due to a mutation at the X-linked mottled locus (Mo). The mutant mice are hypopigmented and die at around 15 days after birth, but can be saved by treatment with copper before the 10th postnatal day. Menkes disease has been shown to be due to mutations of the gene ATP7A which encodes P-type ATPase (referred to here as MNK). MNK is likely to function in copper efflux from cells, but the full range of its biological activity is not fully understood. The nature of the mutation in the brindled mouse is of importance in our understanding of the role of MNK and for devising treatment strategies for Menkes disease. Here we show that the brindled mouse has a deletion of two amino acids in a highly conserved, but functionally uncharacterized, region of Mnk. Comparison with the Ca ATPases suggests this region may be involved in conformational changes associated with the E1/E2 transition fundamental to the action of P-type ATPases. We also describe the first Western blot data for Mnk in tissues, and these show normal levels of Mnk in mutant and brindled kidneys but none in liver. In the kidney, immunohistochemistry demonstrated Mnk in the proximal and distal tubules, the distribution is identical in mutant and normal. This distribution is consistent with Mnk being involved in copper resorption from the urine.
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PMID:Molecular basis of the brindled mouse mutant (Mo(br)): a murine model of Menkes disease. 921 72

The Menkes ATPase is the product of the MNK gene, defective in some inherited human disorders of copper metabolism. We here show the formation of an acylphosphate intermediate by the murine MNK homologue in membranes from normal and copper resistant Chinese hamster ovary cells. In the latter, fivefold higher levels of acylphosphate were formed. Challenging these cells with copper, which induces relocation of the MNK ATPase from the trans-Golgi network to the plasma membrane, did not influence acylphosphate formation. The kinetics of phosphorylation, metal dependence, and sensitivity to inhibitors were investigated. The results show that the MNK ATPase is an active P-type ATPase and provide a direct functional test for this enzyme.
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PMID:Acylphosphate formation by the Menkes copper ATPase. 925 13

Copper is an essential trace element in prokaryotes and eukaryotes and is strictly regulated by biological mechanisms. Menkes and Wilson diseases are human disorders that arise from disruption of the normal process of copper export from the cytosol to the extracellular environment. Recently a gene for Wilson disease (WD)(also named the ATP7B gene) was cloned. This gene encodes a copper transporter of the P-type ATPase. We prepared monoclonal and polyclonal anti-(WD protein) antibodies and characterized the full-length WD protein as well as a shorter form that is produced by alternative splicing in the human brain. We found that the WD protein is localized mainly in the Golgi apparatus, whereas the shorter form is present in the cytosol. These results suggest that the alternative WD proteins act as key regulators of copper metabolism, perhaps by performing distinct roles in the intracellular transport and export of copper.
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PMID:Two forms of Wilson disease protein produced by alternative splicing are localized in distinct cellular compartments. 930 43

The CCC2 gene in the yeast Saccharomyces cerevisiae encodes a P-type ATPase (Ccc2p) required for the export of cytosolic copper to the extracytosolic domain of a copper-dependent oxidase, Fet3p. Ccc2p appears to be both a structural and functional homolog of ATPases impaired in two human disorders of intracellular copper transport, Menkes disease and Wilson disease. In the present work, three approaches were used to determine the locus of Ccc2p-dependent copper export within the secretory pathway. First, like ccc2 mutants, sec mutants blocked in the secretory pathway at steps prior to and including the Golgi complex failed to deliver radioactive copper to Fet3p. Second, also like ccc2 mutants, vps33 and certain other mutants with defects in post-Golgi sorting exhibited phenotypes traceable to deficient copper delivery to Fet3p. These findings were sufficient to explain the respiratory deficiency of these mutants. Third, immunofluorescence microscopy revealed that Ccc2p was distributed among several punctate foci within wild-type cells, consistent with late Golgi or post-Golgi localization. Thus, copper export by Ccc2p appears to be restricted to a late or post-Golgi compartment in the secretory pathway.
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PMID:Restriction of copper export in Saccharomyces cerevisiae to a late Golgi or post-Golgi compartment in the secretory pathway. 932 7

The full-length cDNA coding for a putative copper transporting P-type ATPase (Cu2+-ATPase) was cloned from Caenorhabditis elegans. The putative Cu2+-ATPase is a 1,238-amino acid protein, and highly homologous to the Menkes and Wilson disease gene products mutations of which are responsible for human defects of copper metabolism. The Saccharomyces cerevisiae mutant with a disrupted CCC2 gene (yeast Menkes/Wilson disease gene homologue) was rescued by the cDNA for the C. elegans Cu2+-ATPase but not by the cDNA with an Asp-786 (an invariant phosphorylation site) to Asn mutation, suggesting that the C. elegans Cu2+-ATPase functions as a copper transporter in yeast. The expressed C. elegans protein was detected in yeast vacuolar membranes by immunofluorescence microscopy. The yeast expression system may facilitate further studies on copper transporting P-type ATPases.
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PMID:Caenorhabditis elegans cDNA for a Menkes/Wilson disease gene homologue and its function in a yeast CCC2 gene deletion mutant. 935 93

We previously reported that copper efflux from C6 rat glioma cells was blocked by a brief exposure to sulfhydryl reagents p-chloromercuribenzoate (PCMB) and iodoacetamide as well as dicyclohexylcarbodiimide, suggesting the possible involvement of a Cu-transporting ATPase in the efflux mechanism. In this report, we show that copper efflux from PC12 cells, a neuron-like cell line established from rat adrenal pheochromocytoma, is also inhibited by PCMB exposure. Furthermore, we show that both C6 and PC12 cells express a homolog of the Menkes gene (MNK) as detected by RT-PCR with primers designed from a mouse cDNA and confirmed by sequence analysis of the amplified product. An expected 760-bp fragment representing the transduction and phosphorylation domains and a 925-bp fragment encoding the heavy metal-binding domain of Atp7a were amplified from a RNA extract of C6 and PC12 cells. Sequence data revealed that 690 bp of the 760-bp fragment from C6 cells were an identical match to a similar fragment from PC12 cells. Both fragments encoded a 229 amino-acid polypeptide that had a 98.7% sequence homology to mouse Atp7a. In addition, 880 bp from the 925-bp fragment of the two cell lines were identical and encoded a 293 amino-acid polypeptide with 94.5% sequence homology to mouse Atp7a. These data establish that a Menkes-type Cu-transporting ATPase is expressed in rat C6 and PC12 cells and strongly support the hypothesis that both neurons and glia are involved in maintaining Cu homeostasis in the central nervous system.
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PMID:A Menkes P-type ATPase involved in copper homeostasis in the central nervous system of the rat. 937 50

The gene for Menkes disease, an X-linked disorder of copper transport, has recently been identified and shown to encode a copper-transporting P-type ATPase. The macular mutant mouse has been proposed as an animal model for Menkes disease. In the present study, we report the finding of a missense mutation in the mottled gene of the macular mouse. A single base change, T to C, at nucleotide position 4223, is predicted to result in an amino acid change from serine to proline at residue 1382 in the eighth transmembrane domain. This mutation differs from the 6-bp deletion we find in brindled cDNA. With validation of macular as an animal model of Menkes disease, we compared mottled gene expression in the intestine, kidney, and brain of macular and normal mice. In Northern analyses an 8.3-kb transcript was detected in the intestine, kidney, and brain of both normal and macular mice, with the level of transcript in macular approximately 80% that of normal. In situ hybridization studies revealed that the mottled gene was clearly expressed in intestinal epithelial cells, Paneth cells, and renal proximal tubular cells of both normal and macular mice. In normal brain, mottled gene expression was most intensely observed in the choroid plexus, in Ammon's born and the dentate gyrus in the hippocampus, in Purkinje cells, and the granular layer of the cerebellum. The intensity and localization of the signals in the brain of macular mice were similar to those of the controls. The distribution of expression of mottled is correlated with cells and tissues showing histopathology or abnormal copper sequestration in macular and other mutants.
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PMID:Mutation analysis and expression of the mottled gene in the macular mouse model of Menkes disease. 938 Apr 33


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